In the Qing Dynasty,the study of Ci poetry flourished,and poets placed great emphasis on sound and rhythm.In the creation of Ci poetry,Wan Shu firstly advocated the"Four Tones Theory".After the Qianlong and Jiaqing periods,poets,represented by Jiang Chunlin and the Four Great Masters of the late Qing Dynasty,placed great emphasis on four tone characters in their writing.In the collation of Ci,the method of using four tones to proofread Ci had emerged,which promoted the study of Ci rhythm and the compilation of Ci literature.With the deepening of the study of Ci rhythm,scholars such as Ling Tingkan and Xie Yuanhuai attempted to reconstruct Ci music,while Jiang Shunyi emphasized palace tone and phonetic examination in Ci,and criticized Wan Shu's"Four Tones Theory".In summary,the construction of the"Four Tones Theory"promoted the improvement of the Qing Dynasty's poetic system and the independent development of Ci studies.